Plants to Avoid

Wearing long pants and sleeves is a good way to avoid coming into contact with plants that could cause skin irritation at Severson Dells Nature Center.

Cow Parsnip (Heracleum maximum)

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Heracleum maximum, commonly known as cow parsnip, is the only member of the genus Heracleum native to North America. It is also known as American cow-parsnip, Indian celery, Indian rhubarb or pushki. It is sometimes referred to as Heracleum lanatum. Cow parsnip is a tall herbaceous plant reaching heights of over 2 m (7 ft). The genus name Heracleum (from Heracles) refers to the very large size of all parts of these plants. Cow parsnip has the characteristic flower umbels of the carrot family (Apiaceae). Some of these furanocoumarins found in cow parsnip are known to have antimicrobial properties and are responsible for a rash producing erythematous vesicles (burn-like blisters) and hyperpigmentation that occurs after getting the clear sap onto one's skin. They are photosensitive, with the rash occurring only after exposure to ultraviolet light. Because of this, phytophotodermatitis causing skin blistering may occur after coming into contact with the sap on a sunny day. The scars and pigmentation from these blisters caused by some Heracleum species can last for months or years. (Wikipedia)


Poison Ivy (Toxicodendron radicans)

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Toxicodendron radicans, commonly known as eastern poison ivy or poison ivy, is a poisonous Asian and Eastern North American flowering plant that is well-known for causing urushiol-induced contact dermatitis, an itchy, irritating, and sometimes painful rash, in most people who touch it. The rash is caused by urushiol, a clear liquid compound in the plant's sap. The species is variable in its appearance and habit, as it can be found as a vine, shrub, or forb. Regardless of the growth pattern, poison ivy can be identified by its leaf shape and will have the same toxic effects. Despite its common name, it is not a true ivy (Hedera), but rather a member of the cashew and pistachio family (Anacardiaceae). T. radicans is commonly eaten by many animals, and the seeds are consumed by birds, but poison ivy is most often thought of as an unwelcome weed. (Wikipedia)


Stinging Nettle (Urtica dioica)

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Urtica dioica, often known as common nettle, stinging nettle (although not all plants of this species sting) or nettle leaf, or just a nettle or stinger, is a herbaceous perennial flowering plant in the family Urticaceae. Originally native to Europe, much of temperate Asia and western North Africa, it is now found worldwide. The species is divided into six subspecies, five of which have many hollow stinging hairs called trichomes on the leaves and stems, which act like hypodermic needles, injecting histamine and other chemicals that produce a stinging sensation upon contact ("contact urticaria"). The plant has a long history of use as a source for traditional medicine, food, tea, and textile raw material in ancient societies. The leaves and stems are very hairy with non-stinging hairs, and in most subspecies, also bear many stinging hairs (trichomes or spicules), whose tips come off when touched, transforming the hair into a needle that can inject several chemicals causing a painful sting or paresthesia, giving the species its common names: stinging nettle, burn nettle, burn weed, or burn hazel. (Wikipedia)


Wild Parsnip (Pastinaca sativa)

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Pastinaca Sativa, commonly known as Wild parsnip, is a member of the Umbelliferae (parsnip) family. Rosettes grow close to the ground and bear leaves averaging six inches in height. The plant has a long, thick taproot, which is edible. Flowering plants produce a single, thick stem that contains hundreds of yellow umbellate flowers. The lateral flowers often overtop the terminal flowers. Depending on the habitat and growing conditions, individual flowering plants range to over four feet in height. Leaves are alternate, pinnately compound, branched, and have saw-toothed edges. Each leaf has 5-15 ovate to oblong leaflets with variable toothed edges and deep lobes.

Wild parsnip slowly invades an area in waves following initial infestation. Once the population builds, it spreads rapidly. This species is an aggressive, Eurasian weed that frequently invades and modifies a variety of open habitats.

Wild parsnip can cause phytophotodermatitis to the skin. If the plant juices come in contact with skin in the presence of sunlight, a rash and/or blistering can occur, as well as skin discoloration that may last several months. (SEWISC)